/**
 * All comments in this file are generated by the Databas Wizard, except those
 * marked with ==>
 *
 * ActionScript source file that defines the UI logic and some of the data access code.
 * This file is linked into the main application MXML file using the mx:Script tag.
 * Most of the functions in this file are called by event handlers defined in
 * the MXML.
 */
import mx.collections.ArrayCollection;
import mx.controls.Alert;
import mx.controls.dataGridClasses.DataGridColumn;
import mx.events.CloseEvent;
import mx.events.DataGridEvent;
import mx.managers.CursorManager;
import mx.rpc.AsyncToken;
import mx.rpc.events.FaultEvent;
import mx.rpc.events.ResultEvent;
import mx.rpc.http.mxml.HTTPService;

//include the constant definition of the server endpoint URL
include "radio_stationsconfig.as";

/**
 * gateway : this is the communication layer with the server side php code
 */
private var gateway:HTTPService = new HTTPService();

/**
 * the array collection holds the rows that we use in the grid
 */
[Bindable]
public var dataArr:ArrayCollection = new ArrayCollection();

/**
 * column that we order by. This is updated each time the users clicks on the 
 * grid column header. 
 * see headerRelease="setOrder(event);" in the DataGrid instantiation in the 
 * mxml file
 */
private var orderColumn:Number;


/**
 * the list of fields in the database table
 * needed to parse the response into hashes
 */ 
private var fields:Object = { 'id':Number, 'station_type':String, 'station_name':String, 'callLetters':String, 'city':String, 'state':String, 'homepage':String, 'listen_live_url':String, 'mp3_hs':String, 'wm_hs':String, 'graphic_url':String, 'graphic_h':Number, 'graphic_w':Number};

/**
 * Executes when the mxml is completed loaded. Initialize the Rest Gateway.
 */
private function initApp():void 
{
    /**
     * initialize the gateway
     * - this will take care of server communication and simple xml protocol.
     */
    gateway.url = ENDPOINT_URL;
    gateway.method = "POST";
    gateway.useProxy = false;
    gateway.resultFormat = "e4x";

    /**
     * set the event handler which prevents editing of the primary key
     */
    dataGrid.addEventListener(DataGridEvent.ITEM_EDIT_BEGINNING, editCellHandler);

    /**
     * set the event handler which triggers the update actions - everytime an 
     * edit operation is finished
     */
    dataGrid.addEventListener(DataGridEvent.ITEM_EDIT_END, editCellEnd);

    gateway.addEventListener(ResultEvent.RESULT, resultHandler);
    gateway.addEventListener(FaultEvent.FAULT, faultHandler);
    
    /**
     * ==> Do not display the default view until login success  
     */
    view.visible = false;
	
    /**
      * ==> Display Login Canvas
      */
    goToLogin();
}

/**
 * Disallow editing of the primary key column.
 * @param e DataGridEvent contains details about the row and column of the grid 
 * where the user clicked
 */
private function editCellHandler(e:DataGridEvent):void
{
    /**
     * if the user clicked on the primary key column, stop editing
     */
    if(e.dataField == "idCol")
    {
        e.preventDefault();
        return;
    }
}

/**
 * Click handler for "Filter" button.
 * When setting another filter, refresh the collection, and load the new data
 */
private function filterResults():void
{
    fill();
}

/**
 * Event handler triggered when the user finishes editing an entry
 * triggers an "update" server command
 */
private function editCellEnd(e:DataGridEvent):void
{
    var dsRowIndex:int = e.rowIndex;
    var dsFieldName:String = e.dataField;
    var dsColumnIndex:Number = e.columnIndex;

    var vo:* = dataArr[dsRowIndex];
    
    var col:DataGridColumn = dataGrid.columns[dsColumnIndex];
    var newvalue:String = dataGrid.itemEditorInstance[col.editorDataField];

    trace("a:" + dsRowIndex + ", " + dsFieldName + ", " + dsColumnIndex);

    var parameters:* =
    {
        "id": vo.idCol,        "station_type": vo.station_typeCol,        "station_name": vo.station_nameCol,        "callLetters": vo.callLettersCol,        "city": vo.cityCol,        "state": vo.stateCol,        "homepage": vo.homepageCol,        "listen_live_url": vo.listen_live_urlCol,        "mp3_hs": vo.mp3_hsCol,        "wm_hs": vo.wm_hsCol,        "graphic_url": vo.graphic_urlCol,        "graphic_h": vo.graphic_hCol,        "graphic_w": vo.graphic_wCol    }

	parameters[dsFieldName.substr(0,dsFieldName.length-3)] = newvalue;

	/**
	 * execute the server "update" command
	 */
    doRequest("Update", parameters, saveItemHandler);    

}

/**
 * result handler for the "update" server command.
 * Just alert the error, or do nothing if it's ok - the data has already 
 * been updated in the grid
 */
private function saveItemHandler(e:Object):void
{
    if (e.isError)
    {
        Alert.show("Error: " + e.data.error);
    }
    else
    {
    }     
}

/**
 * dragHeader handler for the datagrid. This handler is executed when the user 
 * clicks on a header column in the datagrid
 * updates the global orderColumn variable, refreshes the TableCollection
 * @param event DataGridEvent details about the column
 */
private function setOrder(event:DataGridEvent):void 
{
    orderColumn = event.columnIndex;
    var col:DataGridColumn = dataGrid.columns[orderColumn];
    col.sortDescending = !col.sortDescending;
    
    event.preventDefault();
    fill();
}

/**
 * Click handler for the "Save" button in the "Add" state
 * collects the information in the form and adds a new object to the collection
 */
private function insertItem():void {
    var parameters:* =
    {
        "method": "Insert",		"station_type": station_typeCol.text,		"station_name": station_nameCol.text,		"callLetters": callLettersCol.text,		"city": cityCol.text,		"state": stateCol.text,		"homepage": homepageCol.text,		"listen_live_url": listen_live_urlCol.text,		"mp3_hs": mp3_hsCol.text,		"wm_hs": wm_hsCol.text,		"graphic_url": graphic_urlCol.text,		"graphic_h": graphic_hCol.text,		"graphic_w": graphic_wCol.text    };

	/**
	 * execute the server "insert" command
	 */
    doRequest("Insert", parameters, insertItemHandler);
}

/**
 * Result handler for the insert call.
 * Alert the error if it exists
 * if the call went through ok, return to the list, and refresh the data
 */
private function insertItemHandler(e:Object):void
{
    if (e.isError)
    {
        Alert.show("Error: " + e.data.error);
    }
    else
    {
        goToView();
        fill();
    }     
}

/** 
 * general utility function for refreshing the data 
 * gets the filtering and ordering, then dispatches a new server call
 *
 */
private function fill():void 
{
    /**
     * find the order parameters
     */
    var desc:Boolean = false;
    var orderField:String = '';
    
    if(!isNaN(orderColumn))
    {
        var col:DataGridColumn = dataGrid.columns[orderColumn];
        desc = col.sortDescending;
		//remove the 'Col' particle
        orderField = col.dataField.substr(0,col.dataField.length-3);
    }

    dataGrid.enabled = false;
    CursorManager.setBusyCursor();

    var parameters:* =
    {
        "orderField": orderField,
        "orderDirection": (desc) ? "DESC" : "ASC", 
        "filter": filterTxt.text
    }
	/**
	 * execute the server "select" command
	 */
    doRequest("FindAll", parameters, fillHandler);
}

/** 
 * result handler for the fill call. 
 * if it is an error, show it to the user, else refill the arraycollection with the new data
 *
 */
private function fillHandler(e:Object):void
{
    if (e.isError)
    {
        Alert.show("Error: " + e.data.error);
    } 
    else
    {
        dataArr.removeAll();
        for each(var row:XML in e.data.row) 
        {
            var temp:* = {};
            for (var key:String in fields) 
            {
                temp[key + 'Col'] = row[key];
            }

            dataArr.addItem(temp);
        }

        CursorManager.removeBusyCursor();
        dataGrid.enabled = true;
    }    
}

/**
 * Click handler for the "delete" button in the list
 * confirms the action and launches the deleteClickHandler function
 */
private function deleteItem():void {
    
    if (dataGrid.selectedItem)
    {
        Alert.show("Are you sure you want to delete the selected record?",
        "Confirm Delete", 3, this, deleteClickHandler);
    }
    
}

/**
 * Event handler function for the Confirm dialog raises when the 
 * Delete button is pressed.
 * If the pressed button was Yes, then the product is deleted.
 * @param object event
 * @return nothing
 */ 
private function deleteClickHandler(event:CloseEvent):void
{
    if (event.detail == Alert.YES) 
    {
        var vo:* = dataGrid.selectedItem;

        var parameters:* =
        {
            "id": vo.idCol
        }

		/**
		 * execute the server "delete" command
		 */
        doRequest("Delete", parameters, deleteHandler);

        setTimeout( function():void
        {
            dataGrid.destroyItemEditor();
        },
        1);
    }
}

public function deleteHandler(e:*):void
{
    if (e.isError)
    {
        Alert.show("Error: " + e.data.error);
    }
    else
    {
        var id:Number = parseInt(e.data.toString(), 10);
        for (var index:Number = 0; index < dataArr.length; index++)
        {
            if (dataArr[index].idCol == id)
            {
                dataArr.removeItemAt(index);
                break;
            }
        }
    }     
}

/**
 * deserializes the xml response
 * handles error cases
 *
 * @param e ResultEvent the server response and details about the connection
 */
public function deserialize(obj:*, e:*):*
{
    var toret:Object = {};
    
    toret.originalEvent = e;
    
    if (obj.data.elements("error").length() > 0)
    {
        toret.isError = true;
        toret.data = obj.data;
    }
    else
    {
        toret.isError = false;
        toret.metadata = obj.metadata;
        toret.data = obj.data;
    }

    return toret;
}

/**
 * result handler for the gateway
 * deserializes the result, and then calls the REAL event handler
 * (set when making a request in the doRequest function)
 *
 * @param e ResultEvent the server response and details about the connection
 */
public function resultHandler(e:ResultEvent):void
{
    var topass:* = deserialize(e.result, e);
    
    var resultString:String;
	resultString = e.result.data.error;
       
    // I added check for Session expiration 
    if (resultString == "Session expired. Please login.") {
    	mx.managers.CursorManager.removeBusyCursor();
    	applicationScreens.selectedChild = login;
    	username.text = "";
    	password.text = "";
    }
    e.token.handler.call(null, topass);
}

/**
 * fault handler for this connection
 *
 * @param e FaultEvent the error object
 */
public function faultHandler(e:FaultEvent):void
{
	var errorMessage:String = "Connection error: " + e.fault.faultString; 
    if (e.fault.faultDetail) 
    { 
        errorMessage += "\n\nAdditional detail: " + e.fault.faultDetail; 
    } 
    Alert.show(errorMessage);
}

/**
 * makes a request to the server using the gateway instance
 *
 * @param method_name String the method name used in the server dispathcer
 * @param parameters Object name value pairs for sending in post
 * @param callback Function function to be called when the call completes
 */
public function doRequest(method_name:String, parameters:Object, callback:Function):void
{
    // add the method to the parameters list
    parameters['method'] = method_name;

    gateway.request = parameters;

    var call:AsyncToken = gateway.send();
    call.request_params = gateway.request;

    call.handler = callback;
}


/**
 * Click handler when the user click the "Create" button
 * Load the "Update" canvas.
 */
public function goToUpdate():void
{
	applicationScreens.selectedChild = update;
}

/**
 * Load the "View" canvas.
 */
public function goToView():void
{
	view.visible = true;	
    applicationScreens.selectedChild = view;
}

/**
 * Load the "Login" canvas.
 *
 * ==> I added the Login capability
 */
public function goToLogin():void
{
    applicationScreens.selectedChild = login;
}

/**
 * ==> I added the Login capability
 */
private function handleLogin(event:ResultEvent):void {
	
    var userAuth:String = event.result as String;
         
  	if (userAuth == username.text + "yes") {
    	loginSuccess();		
	}
  	else {
  		Alert.show("Login Failed");
		username.text = "";
		password.text = "";
	}
}

private function handleAuthorization(event:ResultEvent):void {
	
//to be implemented	 
}

/**
 * ==> I added the Log Out capability
 */
private function handleLogout(event:ResultEvent):void {
	
	var userSession:String = event.result as String;
	if (userSession == "session destroyed") {
    	username.text = "";
    	password.text = "";

		goToLogin();
	}
}

/**
 * ==> I added the Login capability
 */
public function loginSuccess():void
{
	goToView();
	fill();
}